Crystal container



Oct. 24, 1944. a. E. WOODMARK CRYSTAL CONTAINER Filed Jan. 51, 1944 2Sheets-Sheet l Oct. 24, 1944. G. WOODMARK 2,361,343

CRYSTAL CONTAINER Filed Jan. 51, 1944 2 Sheets-Sheet 2 Patented Oct. 24,1944 UNITED STATES PATENT OFFICE CRYSTAL CONTAINER Glenn E. Woodmark,Minneapolis, Minn., assignor to The Maico Company, Incorporated, Min- 20Claims.

My present invention relates to an improved holder and container forcrystals of th kind used in connection with radio sending and re--ceiving sets for tuning the same to operate at a pre-selected radiofrequency and which, crystals, are usually ground to resonate at thesaid selected frequency.

Although crystals of this type are very sensitive to moisture, andparticularly to frozen moisture, no great amount of trouble is usuallyencountered from this source so long as the crystals be covered andprotected against rapid changes in temperature. However, crystals ofthis type are widely used in connection with radio communicationequipment and when so used are subject to rapidly changing altitudeswith consequent rapid changes in temperature which latter, if thecrystal be in communication with the surrounding atmosphere, causesprecipitation and subsequent freezing of moisture on and about thecrystal. Such accumulation of moisture, and particularly frozenmoisture, on the crystal and its associate parts tends to vary thefrequency characteristics of the crystal and sometimes renders thecrystal entirely inoperative, all of which is very objectionable. This,of course, indicates the desirability of hermetically sealing thecrystal, but experience has shown that unless the sealing of the crystalis complete and positive, it is better to leave the same in freecommunication with the surrounding atmosphere so that precipitatedmoisture will be given a, free opportunity to evaporate rather than betrapped and progressively collected.

An important object of my present invention is, therefore, the provisionof a holder and container for crystals of the general characterdescribed provided with external contacts and in which the crystal willbe hermetically sealed.

Another object of the invention is the provision of an improved crystalholding structure that is particularly adapted to hermetic sealing ofthe crystal.

A further object of the invention is the provision of a, hermeticallysealed crystal holder of the plug-in type.

A still further important object of the invention is the provision of animproved plug-in type crystal container wherein the crystal is removablycontained and hermetically sealed.

A still further object of the invention is the provision of an improvedcrystal holder and container having external contacts for connectinginto a circuit and into which the crystal may be quickly and easilyinserted, properly connected to the external contacts, and hermeticallysealed.

A still further object of the invention is the provision of a crystalholder and container of the general character described comprising acasing having a primarily open but normally closed crystal-receivingcavity wherefrom contact ele-- ments extend to the exterior of thecasing, and means whereby the crystal and certain cooperating elementsfor connecting the same to the respective contact elements of the casingmay be rapidly assembled externally of the casing cavity and applied asa unit to the casing cavity.

The above and other highly important objects and advantages of theinvention will be made apparent from the following specification, claimsand appended drawings, which latter illustrate a commercial embodimentof the invention.

In the accompanying drawings, like characters indicate like partsthroughout the several views.

Referring to the drawings:

Fig. 1 is a perspective view of a completely assembled crystal holder ofthe present invention on a. somewhat enlarged scale with respect to thecommercial forms of the device;

Fig. 2 is a transverse vertical sectional view taken on the line 2-2 ofFig. 1 and on a still further enlarged scale;

Fig. 3 is a vertical sectional view taken on the line 3-3 of Fig. 2;

Fig. 4 is a horizontal sectional view taken on the line 4-4 of Fig. 3;

Fig. 5 is a sectional View similar to Fig. 3 but showing the coverremoved and the crystal and certain associated parts partially removedfrom the casing cavity;

Fig. 6 is a transverse section view taken on the line 6-6 of Fig. 5 andsimilar to Fig. 4 but taken lower down the casing and with certain ofthe parts removed; and

Fig. 7 is a composite perspective view of a. drawer-like receptacle andseveral parts including the crystal, a pair of pressure plates, and apair of yielding contacts, all of which are normally assembled togetherfor unitary movements therewith into and out of the casing cavity.

The main casing body of the improved crystal holder is indicated as anentirety by 8, the cavity thereof by 9, and the removable cover of thecasing by ID. The casing body 8 and cover ID are preferably molded of asuitable plastic having very low electric conductivity and consequenthigh insulating qualities. In the preferred embodiment of the inventionillustrated, the casing cavity 9, which is primarily open but isnormally closed by the cover I0, is rectangular in both transvers andvertical section and is provided along opposite walls with stationarystrip contacts II that are adapted to be connected to opposite sides ofan interposed crystal and are connected to opposite terminal prongs I2that project through the end of the casing opposite the cover It)thereof. The projecting ends of the prongs I! are adapted to be pluggedin to suitable sockettype contacts in the radio apparatus. The innerends of said prongs are externally threaded for cooperation withthreaded nuts l3, while the [intermediate portions of the said prongsare shown as being integrally formed with angular nut-shaped flanges Hfor application to a wrench used in screwing the prongs l2 tightly intothe nuts 13.

The stationary strip contacts H of the casing body extend longitudinallyof the casing cavity 9 from the upper primarily open end portion thereofto a point well below the center of the cavity and then extenddiagonally along their respective walls to the bottom of the cavity atwhich point they are turned crosswise of the cavity and are clamped oneunder each of the terminal anchoring nuts 13, the lower out-turned endsof the strip contacts ll bein perforated to receive the threaded endportions of the terminal prongs Hi. In order to positively prevent theleakage of air through the terminal prong-receiving apertures of thecasing body 8, resilient washers l5 (preferably of synthetic rubber) areapplied under' the prong flanges l4 and compressed.

The crystal I8, which is of the conventional variety ground to resonateat a pre-determined radio frequency and may be assumed to be of quartz,is shown as being in the form of a rectangular sheet. This crystal isnormally disposed between a pair of rectangular pressure plates I! whichare yieldingly pressed against the crystal 16 by an opposite pair ofyielding contact elements [8. The pressure plates H (see particularlyFig. 7) are stamped or otherwise formed to provide crystal-engagingbosses IT at their four corners, and it is only these bosses ll of thepressure plates that engage the crystal, thereby leaving the major areaof the crystal free to resonate between the pressure plates.

The crystal l6, pressure plates ll, and yielding contact elements l8,are normally contained within the open central portion I9 of a drawerlike receptacle 20, which latter is externally sized and shaped tofreely,-but snugly, fit within the cavity 9 of the casing body 8, asshown, for example, in Figs. 2, 3, and 4. The open central portion ofthis drawer-like receptacle is shaped to freely, but snugly, receive thecrystal I6, pressure plates [1, and yielding contact elements I8, andall these parts 18, I1, and I8 are assembled in the drawer-likereceptacle externally of the casing cavity 8 and are inserted thereintoand removed therefrom as a unit much in the manner of a cabinet drawer.The yielding contact elements l8, preferably and as shown, have outsidedimensions closely corresponding to those of the crystal i6 and pressureplates [1, so that they, too, will be retained by the drawer-likereceptacle against any material movement with re spect to the pressureplates I1, and these are formed from flat spring metal into outwardlybowed or outwardly convex shape in transverse cross section. Thevertical edges of these yielding contact elements engage the verticaledge portions of the pressure plates and the outwardly bowed centralportions or apexes l8 thereof normally engage opposite contacts H of thecasing body. It is important to note that the normal spacing between theapex portions ill of opposite pressure plates is greater than thespacing between opposite contacts H, so that lateral compression of thecontact elements I8 is a necessary preliminary to insertion of thedrawer-like receptacle and its contained parts lS-I8 inclusive into thecasing cavity. In practice, this is best accomplished by assembling theparts and then squeezing the opposite yielding contact elements l8between the thumb and forefinger of one hand to the extent necessary toinitiate application of the entire unit into the casing cavity to aposition approximately corresponding to that shown in'Fig. 5, afterwhich endwise pressure on the drawer-like receptacle 20 will cause theparts l6, l1, l8, and 20 to slide into operative position as a unit.With this arrangement, the assembled parts are always maintained tightlyclamped together under lateral pressure exerted thereon by the yieldingcontact elements ll, thereby preventing any possible rattling orvibration of parts and assuring good electrical contact therebetween atall times.

From the above, it will be obvious that when the parts are properlyassembled as shown, for example, in Figs. 2, 3, and 4, opposite sides ofthe crystal [6 will be connected to opposite stationary contacts H andthrough said contacts II to opposite contact prongs l2.

When the parts have been duly assembled within the casing cavity, thecover 10 may be applied and anchored in place by means of anchoringscrews 2| that work in internally-threaded nuts 22 in the casing body 8.These anchoring nuts 22 are shown as being closed at their lower endsand as being knurled or otherwise roughened on their outer surfaces andare cast in the molded casing body 8. Final hermetic sealing of thecasing is accomplished by applyin between the cover Ill and easing body8 a resilient gasket 21 which is preferably of synthetic rubber and maybe compressed by tightening of the anchoring screws 2 l,

The crystal holder described is inexpensive, quickly and easilyassembled and disassembled, and hermetically seals the crystal under allthe extreme altitude and temperature variations encountered in aircraftcommunication equipment.

What I claim is:

1. A container for radio crystals comprising a casing body having acavity that is open at one end of the casing body, stationary contactsexposed to the casing cavity and having terminals that project throughthe casing body, a drawerlike receptacle adapted to slide into and outo! the casing cavity and having an openin in its central portion towhich the stationary casing contacts are exposed when the drawer is inoperative position, a crystal, a pair of laterally resilient contactelements electrically connected with opposite sides of the crystal, saidcrystal and said laterally resilient contact elements being disposedwithin the open central portion of the drawer-like receptacle forunitary movements therewith into and out of the casing cavity, saidlaterally resilient contact elements each engaging a different of saidstationary casing contacts when in operative position in the cavity andmaintaining a yielding pressure thereon and the crystal, and a cover forsaid casing cavity.

2. A container for radio crystals comprising a casing body having acavity that is open at one end of the casing body, stationary contactsexposed at opposite sides of the casing cavity and having terminals thatproject through the casing body, a drawer-like receptacle adapted toslide into and out of the casing cavity and having an opening throughits central portion to which the opposite stationary contacts areexposed when the drawer is in operative position, a crystal, a pair ofcontact elements between which the crystal is disposed, one of saidcontact elements being laterally resilient, said crystal and oppositecontact elements being disposed within the open central portion of thedrawer-like receptacle for unitary movements therewith into and out ofthe casing cavity and being laterally removable from said drawer-likereceptacle when the receptacle is removed from the cavity, said contactelements engaging opposite fixed contacts of the casing when inoperative position and said laterally resilient contact elementmaintaining a yielding pressure on the parts interposed between theopposite casing contacts, and a cover for said casing cavity.

3. The structure defined in claim 1 in which the said stationary casingcontacts are in the nature of flat strips and in which the saidterminals thereof are in the nature of prongs that extend through thecasing body.

4. The structure defined in claim 1 in which the casing cavity anddrawer-like receptacle are rectangular and in which the shape anddimensions of the drawer-like receptacle closely correspond to thedimensions and shape of the casing cavity.

5. The structure defined in claim 2 in which the said stationary casingcontacts are in the na- -ture of net strips lying along opposite sidesof the casing cavity and in which the terminals thereof are in thenature of contact prongs that extend through the casing body at its endopposite the opening thereof, said contact strips being elec-- tricallyconnected to opposite of said prongs and extending therefrom toward theopen end of the casing cavity.

6. The structure defined in claim 1 in which the drawer-like receptacleclosely embraces the edges of the crystal and snugly fits in the casingcavity.

7. The structure defined in claim 2 in which the drawer-like receptaclesnugly fits in the casing cavity and closely embraces the edges of thecrystal and opposite contact elements contained therein,

8. The structure defined in claim 1 which further comprises pressureplates also mounted in the opening of said drawer-like receptacle and indirect engagement with opposite side portions of the crystal, theoutside of said drawerdike receptacle closely corresponding in shape anddimensions to that of the casing cavity, and said drawerlike receptacleclosely embracing the edges of said crystal and pressure plates.

9. A container for radio crystals comprising a casing body having acavity that is open at one end of the casing body, stationary contactsex posed at opposite sides of the casing cavity and having terminalsthat project through the casing, a drawer-like receptacle adapted toslide into and out of the casing cavity and having an open centralportion to which the opposite stationary contacts are exposed when thedrawer like receptacle is in operative position, a crystal, a pair oflaterally yielding contact elements between which the crystal isdisposed, said crystal and opposite laterally yielding contact elementsbeing disposed within the open central portion of the drawer-likereceptacle for unitary movements therewith into and out of the casingcavity and being laterally removable from said drawer-like receptaclewhen the receptacle is removed from the casing cavity, said yieldingcontact elements engaging the opposite fixed contacts of the casingwhen. in operative position and maintaining a yielding pressure thereonand the interposed crystal, and a cover for said casing cavity.

10. A container for radio crystals comprising a casing body having acavity that is open at one end of the casing body, stationarycontacts'exposed at opposite sides of the casing cavity and havingterminals that project through the casing, a drawer-like receptacleadapted to slide into and out of the casing cavity and having an opencentral portion to which said stationary contacts are exposed when thereceptacle is in operative position, a crystal, a pair of pressureplates between which the crystal is disposed, and a pair of laterallyyielding contact elements engaging the outside faces of oppositepressure plates, said crystal, pressure plates, and laterally yieldingcontact elements being disposed within the open central portion of thedrawer-like receptacle for unitary sliding movements therewith into andout of the casing cavity and being laterally removable therefrom whenremoved from the casing cavity, said yielding contact elements engagingthe opposite fixed contacts of the casing when in operative position andexerting yielding squeezing pressure on the interposed pressure platesand crystal, and a cover for said casing cavity.

11. The structure defined in claim 9 in which the said stationarycontacts are in the nature of fiat strips lying along opposite sides ofthe casing cavity and in which the said terminals are in the nature ofprongs that extend through the end of the casing opposite the primarilyopen end thereof, said contact strips being electrically sions of thedrawer-like receptacle closely corre-,,,

spond to the inside dimensions of the cavity.

13. The structure defined in claim 10 in which the casing cavity anddrawer-like receptacle are rectangular and in which the shape anddimensions of the drawer-like receptacleclosely correspond to the insidedimensions of the cavity.

14. The structure defined in claim 10 in which the said stationarycontacts are in the nature ,of flat strips lying along opposite sides ofthe casing cavity and in which the said terminals are in the nature ofprongs that extend through the end of the casing opposite the primarilyopen end thereof, said contact strips being electrically connected toopposite of said prongs and extending therefrom toward the open end ofthe casing cavity.

15. The structure defined in claim 9 in which the drawer-like receptacleclosely embraces the edges of the crystal and laterally yielding contactelements.

16. The structure defined in claim 10 in which i to snugly fit in saidcavity, the central opening in said drawer-like receptacle beingsubstantially rectangular and closely embracing the edge portions of thecrystal and laterally yielding contact elements.

18. The structure defined in claim 10 in which the casing cavity issubstantially rectangular in both longitudinal and transverse crosssection and in which the drawer-like receptacle is shaped to snugly fitin said cavity, the central opening in said drawer-like receptacle beingsubstantially rectangular and closely embracing the edge portions of thecrystal, pressure plates, and laterally yielding contact elements.

19. The structure defined in claim 9 in which the casing cavity issubstantially rectangular in both longitudinal and transverse crosssection and in which the drawer-like receptacle is shaped to snugly fitin said cavity, the central opening in said drawer-like receptacle beingsubstantially rectangular and closely embracing the edge portions of thecrystal and laterally yielding contact elements, said laterally yieldingcontact elements being in the nature or outwardly convex sheet metalsprings with their apexes in engagement with the stationary contacts.

20. The structure defined in claim 10 in which the casing cavity issubstantially rectangular in both longitudinal and transverse crosssection and in which the drawer-like receptacle is shaped to snugly fitin said cavity, the central opening in said drawer-like receptacle beingsubstantially rectangular and closely embracing the edge portions of thecrystal and laterally yielding contact elements, said laterally yieldingcontact elements being in the nature of outwardly convex sheet metalsprings with their apexes in engagement with the stationary contacts.

GLENN E. WOODMARK.

